Displaying system, method, and vehicle

ABSTRACT

The embodiments disclosed in this application describe a displaying system, a displaying method, and a head-up display. The heads-up displaying system includes a display window including a transflective film, an image source emitting light incident on the imaging window, and the light emitted by the image source before reaching the transflective film only comprising s-polarized light. The transflective film is configured to directly reflect a first portion of the s-polarized light emitted from the image source. The transparent substrate reflects a second portion of the s-polarized light, and transmits a third portion of the s-polarized light to the air, the first portion of the s-polarized light, the second portion of the s-polarized light and the third portion of the s-polarized light are all s-polarized light.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Ser. No.15/461,506 filed on Mar. 17, 2017 which claims priority to CNApplication No. 2016101511427, filed on Mar. 17, 2016, and CNApplication No. 2016109711436, filed on Nov. 9, 2016, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The embodiments of the present disclosure relate to the field ofoptoelectronic technology, and more particularly, to a displaying systemand a corresponding imaging method; and also to a vehicle including thedisplaying system.

BACKGROUND

A transparent displaying system typically consists of an image sourceand an imaging window. In existing transparent displaying systems, thereare a variety of choices for the image source and the imaging window. Animaging window is usually composed of a substrate and a reflectivesurface, and most of the imaging windows adopt the structure in whichthe reflective surface serves as an interlayer in the substrate.

In the prior art, there are technical solutions utilizing a sourceemitting p-polarized light as the image source. For example, an imagingmethod using p-polarized light is mentioned in Chinese PatentPublications CN204143067U and CN104267498A, U.S. Pat. Nos. 6,952,312B2;7,123,418B2; and 7,355,796B2, and European Patent ApplicationEP0836108A2.

These p-polarized light based imaging methods, however, generally havethe following drawbacks: if a relatively high reflectivity is required,then the transmissivity will be lowered, thereby reducing the viewingeffect of the external environment, resulting in a relatively highdemand on the brightness of the image source.

For example, when such methods are applied to a head-up display, a darkspot will be formed in the front window. If a relatively hightransmissivity is required, the reflectivity will be lowered; in orderto achieve a good imaging effect, there will be a relatively high demandon the brightness of the image source, which increases cost on powerdissipation of the image source and the like.

In the prior art, a technique using a source that emits s-polarizedlight as the image source has been proposed. For example, U.S. PublishedPatent Application No. US2005012682 and Japanese Patent JP2-141720A bothmention an imaging method using s-polarized light. However, suchs-polarized light-based imaging methods have the following drawbacks:

1. a ghost image can be easily generated;

2. if a relatively high reflectivity is required, then thetransmissivity will be reduced, thus reducing the viewing effect of theexternal environment.

Chinese patent CN2694293Y discloses a full color multiband stack filmapplied in a head-up display which utilizes the interference principleof the multi-layer film of the dielectric layer. The disadvantage ofthis technique is that the transmissivity of light of a specificwavelength is not high. For example, the low transmissivity forparticular wavelengths such as red, green, blue light will greatlyreduce the light (red, green, yellow light) emitted from traffic signallamps, causing a potential safety hazard. Moreover, the imaging angle ofthe technique is limited, and the imaging effect is not good; besides,the technique requires coating about 70 layers of films, so that themanufacturing process is too complicated.

SUMMARY

A displaying system, a displaying method and a vehicle having thedisplaying system are provided in the technical solution of the presentdisclosure.

According to an embodiment of the present disclosure, a displayingsystem, comprises: an imaging window comprising a transparent substrateand a transflective film attached to a first surface of the transparentsubstrate; an image source emitting light incident on the imagingwindow, and the light emitted by the image source before reaching thetransflective film only comprising s-polarized light. The transflectivefilm is formed by stacking at least two types of film layers havingdifferent refractive indexes, the transflective film comprises a firstside and a second side opposite to each other, the first side isattached to the first surface of the transparent substrate, the secondside is in contact with the air, the second side is configured todirectly reflect a first portion of the s-polarized light emitted fromthe image source to an observation region, and the image source and theobservation region are located on a same side of the transflective film,and the transparent substrate comprises a second surface opposite to thefirst surface, the second surface reflects a second portion of thes-polarized light, and transmits a third portion of the s-polarizedlight to the air, the first portion of the s-polarized light, the secondportion of the s-polarized light and the third portion of thes-polarized light are all s-polarized light.

For example, the s-polarized light emitted by the image source beforereaching the transflective film has N spectral lines or bands in avisible light band, N is a positive integer not less than 1; the Nspectral lines or bands each have a FWHM (full-width at half-maximum)equal to or less than 60 nm, and for each of the N spectral lines orbands in a visible spectra of the s-polarized light emitted from theimage source, a major band is defined as a spectra band centered at apeak of the line or the band and expanding up to the FWHM; thetransflective film reflects the s-polarized light at a first angle withrespect to a normal line, and transmits ambient light at a second anglewith respect to the normal line, the first angle is in a range from 30to 89 degrees, and the second angle is in a range from 30 degrees to 80degrees; at the first angle, the transflective film has an averagereflectivity greater than 50% for at least one of the N major bands ofthe s-polarized light, at the second angle, the transflective film hasan average transmissivity greater than 60% for p-polarized light in avisible range.

For example, the N spectral lines or bands comprise at least threespectral lines or bands, a peak position of a first spectral line orband is in a range from 410 nm to 480 nm, a peak position of a secondspectral line or band is in a range from 500 nm to 565 nm, and a peakposition of a third spectral line or band is in a range from 590 nm to690 nm.

For example, the average reflectivity of the transflective film for thethree spectral lines or bands of the s-polarized light is greater than60%, an average transmissivity of the transflective film for thes-polarized light outside the FWHM of the three spectral lines or bandsis greater than 60%.

For example, the peak position of the first spectral line or band is ina range from 440 nm to 460 nm, the peak position of the second spectralline or band is in a range from 530 nm to 550 nm, and the peak positionof the third spectral line or band is in a range from 620 nm to 640 nm,and the average reflectivity of the transflective film for the threespectral lines or bands of the s-polarized light is greater than 70%, anaverage transmissivity of the transflective film for the s-polarizedlight outside the FWHM of the three spectral lines or bands is greaterthan 70%, and the transflective film has the average transmissivitygreater than 95% for the p-polarized light in the visible range.

For example, the peak position of the first spectral line or band is ina range from 444 nm to 446 nm, the peak position of the second spectralline or band is in a range from 531 nm to 533 nm, and the peak positionof the third spectral line or band is in a range from 634 nm to 636 nm,and the first angle is in a range from 55 degrees to 65 degrees, theaverage reflectivity of the transflective film for the three spectrallines or bands of the s-polarized light is greater than 95% at the firstangle, an average transmissivity of the transflective film for thes-polarized light outside the FWHM of the three spectral lines or bandsis greater than 95%, and the transflective film has the averagetransmissivity greater than 95% for p-polarized light in the visiblerange.

For example, the composition of each of the at least two types of filmlayers is at least one selected from the group consisting of tantalumpentoxide, titanium oxide, magnesium oxide, zinc oxide, zirconium oxide,silicon dioxide, magnesium fluoride, silicon nitride, siliconoxynitride, and aluminum fluoride.

For example, an anti-reflection film is disposed on the second surfaceof the transparent substrate, the anti-reflection film reflects thesecond portion of the s-polarized light and transmits the third portionof the s-polarized light to the air; and the anti-reflection filmincreases an average transmissivity of the imaging window for visiblelight by at least 3% or more as compared with a situation where theanti-reflection film is not disposed.

For example, the s-polarized light emitted by the image source beforereaching the transflective film has N spectral lines or bands in avisible light band, N is a positive integer not less than 1; the Nspectral lines or bands each have a FWHM (full-width at half-maximum)equal to or less than 60 nm, and for each of the N spectral lines orbands in a visible spectra of the s-polarized light emitted from theimage source, a major band is defined as a spectra band centered at apeak of the line or the band and expanding up to the FWHM; thetransflective film reflects the s-polarized light at a first angle withrespect to a normal line, and transmits ambient light at a second anglewith respect to the normal line, the first angle is in a range from 30to 89 degrees, and the second angle is in a range from 30 degrees to 80degrees; at the first angle, the transflective film has an averagereflectivity in a range from 25% to 50% for the N major bands of thes-polarized light; at the second angle, the transflective film has anaverage transmissivity greater than 60% for p-polarized light in avisible range.

According to another embodiment of the present disclosure, there isprovided a vehicle comprising a displaying system as mentioned above.

For example, the s-polarized light emitted by the image source beforereaching the transflective film has N spectral lines or bands in avisible light band, N is a positive integer not less than 1; the Nspectral lines or bands each have a FWHM (full-width at half-maximum)equal to or less than 60 nm, and for each of the N spectral lines orbands in a visible spectra of the s-polarized light emitted from theimage source, a major band is defined as a spectra band centered at apeak of the line or the band and expanding up to the FWHM; thetransflective film reflects the s-polarized light at a first angle withrespect to a normal line, and transmits ambient light at a second anglewith respect to the normal line, the first angle is in a range from 30to 89 degrees, and the second angle is in a range from 30 degrees to 80degrees; at the first angle, the transflective film has an averagereflectivity greater than 50% for at least one of the N major bands ofthe s-polarized light, at the second angle, the transflective film hasan average transmissivity greater than 60% for p-polarized light in avisible range.

For example, the N spectral lines or bands comprise at least threespectral lines or bands, a peak position of a first spectral line orband is in a range from 410 nm to 480 nm, a peak position of a secondspectral line or band is in a range from 500 nm to 565 nm, and a peakposition of a third spectral line or band is in a range from 590 nm to690 nm, the average reflectivity of the transflective film for the threespectral lines or bands of the s-polarized light is greater than 60%, anaverage transmissivity of the transflective film for the s-polarizedlight outside the FWHM of the three spectral lines or bands is greaterthan 60%.

For example, an anti-reflection film is disposed on the second surfaceof the transparent substrate, the anti-reflection film reflects thesecond portion of the s-polarized light and transmits the third portionof the s-polarized light to the air; and the anti-reflection filmincreases an average transmissivity of the imaging window for visiblelight by at least 3% or more as compared with a situation where theanti-reflection film is not disposed.

For example, the s-polarized light emitted by the image source beforereaching the transflective film has N spectral lines or bands in avisible light band, N is a positive integer not less than 1; the Nspectral lines or bands each have a FWHM (full-width at half-maximum)equal to or less than 60 nm, and for each of the N spectral lines orbands in a visible spectra of the s-polarized light emitted from theimage source, a major band is defined as a spectra band centered at apeak of the line or the band and expanding up to the FWHM; thetransflective film reflects the s-polarized light at a first angle withrespect to a normal line, and transmits ambient light at a second anglewith respect to the normal line, the first angle is in a range from 30to 89 degrees, and the second angle is in a range from 30 degrees to 80degrees; at the first angle, the transflective film has an averagereflectivity in a range from 25% to 50% for the N major bands of thes-polarized light; at the second angle, the transflective film has anaverage transmissivity greater than 60% for p-polarized light in avisible range.

According to a further embodiment of the present disclosure, there isprovided a displaying system, comprising: an imaging window comprising atransparent substrate and a transflective film attached to a firstsurface of the transparent substrate; an image source emitting lightincident on the imaging window, and the light emitted by the imagesource before reaching the transflective film only comprisings-polarized light. The transflective film is formed by stacking at leasttwo types of film layers having different refractive indexes, thetransflective film comprises a first side and a second side opposite toeach other, the first side is attached to the first surface of thetransparent substrate, the second side is in contact with the air, thesecond side is configured to directly reflect the s-polarized lightemitted from the image source to an observation region, and the imagesource and the observation region are located on a same side of thetransflective film, the s-polarized light emitted by the image sourcebefore reaching the transflective film has N spectral lines or bands ina visible light band, N is a positive integer not less than 1; the Nspectral lines or bands each have a FWHM (full-width at half-maximum)equal to or less than 60 nm, and for each of the N spectral lines orbands in a visible spectra of the s-polarized light emitted from theimage source, a major band is defined as a spectra band centered at apeak of the line or the band and expanding up to the FWHM; thetransflective film reflects the s-polarized light at a first angle withrespect to a normal line, and transmits ambient light at a second anglewith respect to the normal line; the first angle is in a range from 50to 75 degrees, and the second angle is in a range from 55 degrees to 70degrees; at the first angle, the transflective film has an averagereflectivity greater than 50% for at least one of the N major bands ofthe s-polarized light; at the second angle, the transflective film hasan average transmissivity greater than 60% for p-polarized light in avisible range.

For example, the N spectral lines or bands comprise at least threespectral lines or bands, a peak position of a first spectral line orband is in a range from 410 nm to 480 nm, a peak position of a secondspectral line or band is in a range from 500 nm to 565 nm, and a peakposition of a third spectral line or band is in a range from 590 nm to690 nm, and the average reflectivity of the transflective film for thethree spectral lines or bands of the s-polarized light is greater than60%, an average transmissivity of the transflective film for thes-polarized light outside the FWHM of the three spectral lines or bandsis greater than 60%.

For example, the peak position of the first spectral line or band is ina range from 440 nm to 460 nm, the peak position of the second spectralline or band is in a range from 530 nm to 550 nm, and the peak positionof the third spectral line or band is in a range from 620 nm to 640 nm,and the average reflectivity of the transflective film for the threespectral lines or bands of the s-polarized light is greater than 70%, anaverage transmissivity of the transflective film for the s-polarizedlight outside the FWHM of the three spectral lines or bands is greaterthan 70%, and the transflective film has the average transmissivitygreater than 95% for the p-polarized light in the visible range.

For example, the peak position of the first spectral line or band is ina range from 444 nm to 446 nm, the peak position of the second spectralline or band is in a range from 531 nm to 533 nm, and the peak positionof the third spectral line or band is in a range from 634 nm to 636 nm,and the first angle is in a range from 55 degrees to 65 degrees, theaverage reflectivity of the transflective film for the three spectrallines or bands of the s-polarized light is greater than 95% at the firstangle, an average transmissivity of the transflective film for thes-polarized light outside the FWHM of the three spectral lines or bandsis greater than 95%, and the transflective film has the averagetransmissivity greater than 95% for p-polarized light in the visiblerange.

For example, the composition of each of the at least two types of filmlayers is at least one selected from the group consisting of tantalumpentoxide, titanium oxide, magnesium oxide, zinc oxide, zirconium oxide,silicon dioxide, magnesium fluoride, silicon nitride, siliconoxynitride, and aluminum fluoride.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the presentdisclosure or the technical solutions of the prior art, the drawingsused for describing the embodiments or the prior art will be brieflydescribed below. It will be apparent that the drawings described belowmerely describe parts of the embodiments of the present disclosure.These drawings are not to be construed as limiting the disclosure, butare illustrative.

FIG. 1 is an exemplary structural diagram of a displaying systemaccording to one embodiment of the present disclosure;

FIG. 2 is an exemplary schematic diagram showing the distribution ofthree spectral lines or bands according to one embodiment of the presentdisclosure;

FIG. 3 is an exemplary structural diagram of an imaging window accordingto one embodiment of the present disclosure; and

FIG. 4 is an exemplary flow chart of a displaying method according to anembodiment of the present disclosure;

FIG. 5 schematically shows p-polarized light according to one embodimentof the present disclosure;

FIG. 6 schematically shows s-polarized light according to one accordingto one embodiment of the present disclosure;

FIG. 7 schematically shows s-polarized light according to one embodimentof the present disclosure;

FIG. 8 schematically shows p-polarized light according to one embodimentof the present disclosure; and

FIG. 9 schematically shows s-polarized light according to an embodimentof the present disclosure.

DETAILED DESCRIPTION

In order to make the object, technical solution and advantages of thepresent disclosure clearer, the present disclosure will be described infurther detail with reference to the accompanying drawings.

For purposes of brevity and intuition, the solution of the embodimentsof the present disclosure will be described by describing a number ofrepresentative embodiments. Numerous details in the embodiments areprovided solely to aid in understanding the embodiments of the presentdisclosure. It will be apparent that the technical solution of thedisclosure may be implemented without being limited to these details. Inorder to avoid unnecessarily obscuring embodiments of the presentdisclosure, some embodiments are not described in detail, but onlyframes are presented. In the following text, “comprising” means“comprising, but is not limited to . . . ”, “according to . . . ” means“at least according to, but not limited to . . . ”, and “first”,“second” and the like are used for reference to a feature only and arenot intended to impose any limitation, e.g., a sequential limitation, onthe feature. Due to the habit in Chinese language, when the number of acomponent is not specified, it means that the component can be one ormore, or can be understood as at least one.

FIG. 1 is an exemplary structural diagram of a displaying systemaccording to at least one embodiment of the present disclosure.

As shown in FIG. 1, the system includes an image source 1 and an imagingwindow 2. The imaging window 2 includes a transparent substrate and atransflective film 3 attached to one side of the substrate. The imagesource 1 can emit s-polarized light. For example, light emitted by theimage source 1 before reaching the transflective film 3 only includesthe s-polarized light. The s-polarized light has N spectral lines orbands in the visible light band, N is a positive integer not less than1, and the FWHM (full-width at half-maximum) of the spectral lines orbands is 60 nm or less. The s-polarized light is incident on the imagingwindow 2 through the transflective film 3. The transflective film 3 hasan average reflectivity greater than 50% for a waveband within the FWHMof at least one of the N spectral lines or bands of the s-polarizedlight emitted by the image source. The imaging window 2 can also allowtransmission of ambient light. For example, as illustrated in FIG. 1,the imaging window 2 further includes an anti-reflection film 4 (forexample, an anti-reflection film may not be used in other embodiments),which is attached to the other side of the substrate. Theanti-reflection film 4 can increase the ambient light transmissivity ofthe imaging window 2.

The image source 1 may be a displaying apparatus, or a virtual image ora real image formed by such displaying apparatus.

For example, the displaying apparatus may be a liquid crystal screen,where the backlight light source of the liquid crystal screen may be atleast one selected from the group consisting of a laser, a lightemitting diode, an organic light emitting diode, an excited fluorescentlight emitting material, and a quantum dot excitation light source; thedisplaying apparatus may also be an active emitting lattice screencomposed of a light-emitting point light source such as an LED, an OLED,a plasma light emitting point, or the like; the displaying apparatus mayalso be a projection imaging system based on such projection techniquessuch as DLP, LCOS and LCD, with the light source of LED, OLED, laser, orfluorescent light source or a combination thereof, reflected ortransmitted through a display panel such as a DMD, an LCOS, and an LCD,and projected onto a projection screen via a projection lens forimaging; the displaying apparatus may also be a projection imagingsystem which images as the laser beams scan on a screen.

The real or virtual image formed by all the above-mentioned displayingapparatuses through a single or multiple times of refractions orreflections can also be used as an image source.

The substrate of the imaging window 2 may be made of a transparentmaterial such as a PC resin, a PET resin, a PMMA resin, glass, quartz,or the like, and may also be subjected to a special treatment to haveboth transparent and color-changing properties. For example, in stronglight conditions, the substrate may change color to reduce ambient lightintensity.

The transflective film 3 may be arranged to cover the entire innersurface of the substrate, or may cover part of the inner surface of thesubstrate. The transflective film 3 may be a single layer film or formedby stacking multiple film layers having different refractive indexes,where the composition of each film layer may be at least one selectedfrom the group consisting of oxides, fluorides, nitrides, and the like,such as tantalum pentoxide, titanium oxide, magnesium oxide, zinc oxide,zirconium oxide, silicon dioxide, magnesium fluoride, silicon nitride,silicon oxynitride, aluminum fluoride and the like.

The higher the average reflectivity of the transflective film 3 for thes-polarized light in the visible light range, the greater the intensityof the visible light reflected by the transflective film 3 to theobserver. It has been found through tests that the average reflectivityof the transflective film 3 for wavebands within FWHM of at least one ofthe N spectral lines or bands of the s-polarized light emitted by theimage source is greater than a specific reflectivity, for example,greater than 50%, for example, greater than 60%, 70%, 80%, or 90%, andfor example, greater than 95%; the average reflectivity of thetransflective film 3 for visible light band outside the FWHM of the Nspectral lines or bands of the s-polarized light emitted by the imagesource is lower than the average reflectivity of the transflective film3 for the waveband within FWHM of the N spectral lines or bands of thes-polarized light emitted by the image source which is greater than thespecific reflectivity by at least 5%, for example, 10%, 15%, or even20%. In addition, the transflective film 3 has an average transmissivitygreater than 60%, for example, greater than 70%, 80%, or 90%, forexample, even more than 95% for p-polarized light in the visible lightrange.

In some embodiments, the average reflectivity of the transflective film3 for a waveband within FWHM of the N spectral lines or bands of thes-polarized light emitted by the image source 1 is not greater than 50%,but in the range between 25% and 50%. In this case, an anti-reflectionfilm 4 should be used (the anti-reflection film 4 will be described indetail later).

In one embodiment, the s-polarized light incident on the transflectivefilm 3 from the image source has three spectral lines or bands in thevisible light band. The average reflectivity of the transflective film 3for a waveband within the FWHM of the three spectral lines or bands isgreater than 50%. The average reflectivity of the transflective film 3for visible light band outside the FWHM of the three spectral lines orbands of the s-polarized light emitted from the image source 1 is lowerthan the average reflectivity (which is greater than 50%) of thetransflective film 3 for the waveband within the FWHM of the threespectral lines or bands of the s-polarized light emitted from the imagesource by at least 5% or even 10%. In addition, the transflective filmhas an average transmissivity greater than 60% for p-polarized light inthe visible light range.

In another embodiment, the s-polarized light incident on thetransflective film 3 from the image source also has three spectral linesor bands in the visible light band. However, the transflective film 3has an average reflectivity greater than 50% for the waveband within theFWHM of just one or two of the three spectral lines or bands. Thetransflective film 3 has an average reflectivity for the visible lightband outside the FWHM of the three spectral lines or bands of thes-polarized light emitted from the image source 1 lower than the averagereflectivity (which is greater than 50%) for the waveband within theFWHM of the three spectral lines or bands of the s-polarized lightemitted from the image source by at least 5% or even 10%.

It is to be understood that in another embodiment, the number ofspectral lines or bands of the s-polarized light incident on thetransflective film 3 from the image source in the visible light band maybe any positive integer not less than 1 (denoted by n). Thetransflective film 3 has an average reflectivity greater than 50% for awaveband within the FWHM of at least one of the N spectral lines orbands. The transflective film 3 has an average reflectivity for thevisible light band outside the FWHM of the N spectral lines or bands ofthe s-polarized light emitted from the image source 1 lower than theaverage reflectivity (which is greater than 50%) for a waveband withinthe FWHM of the N spectral lines or bands of the s-polarized lightemitted from the image source by at least 5% or even 10%.

Similar to the transflective film 3, the anti-reflection film 4 maycover the entire outer surface of the substrate, or may cover only aportion of the outer surface of the substrate. The anti-reflection filmincreases the average transmissivity of the imaging window for visiblelight by more than 3%.

As shown in FIG. 1, the incident angle of the s-polarized light to thetransflective film 3 is a, where a ranges from 30 to 89 degrees. Inorder to achieve a better reflection and transmission effect, the valueof a is close to the angle tan−1(n2/n1), where n1 is the refractiveindex of the incident medium and n2 is the refractive index of thesubstrate medium. For example, when n1=1.0, n2=1.52, then tan-1(n2/n1)is about 56 degrees 40 minutes; when n1=1.0, n2=1.58, tan−1(n2/n1) isabout 57 degrees 40 minutes; when n1=1.0, n2=1.49, tan−1 (n2/n1) isabout 56 degrees 08 minutes. The range from a is in the range from 50 to75 degrees.

The range and angles of a have been exemplified above and those skilledin the art will appreciate that depending on the refractive index of thesubstrate medium and the refractive index of the incident medium, theangle of a may also be in other ranges.

As further shown in FIG. 1, there is an angle θ between the image source1 and the imaging window 2, the angle θ is in the range from 20 to 70degrees. Of course, the angle θ may also be a value in other ranges; forexample, in some embodiments, the angle θ ranges from 80 degrees to 90degrees.

The spectrum of image source 1 can include one or several monochromaticspectral lines bands. For example, with reference to the exemplaryschematic diagram of the source image spectrum shown in FIG. 2, in orderto display color image, the s-polarized light emitted by the imagesource 1 may be superimposed by three spectral line or banddistributions having the peak in the range from 590 nm to 690 nm (red),500 nm to 565 nm (green), 410 nm to 480 nm (blue), respectively. Theaverage reflectivity of the transflective film 3 for s-polarizedwavebands within the FWHM of the three spectral lines or bands isgreater than 60%. For example, the average transmissivity of thetransflective film 3 for s-polarized light outside the FWHM of the threespectral lines or bands is greater than 60%.

In an embodiment, the light source of the image source consists of athree-color laser with the peak positions of the three colors being 445nm (blue), 532 nm (green), 635 nm (red), respectively. The FWHM of eachpeak is only about 1-2 nm (see the laser projection spectrum indicatedby the solid line in FIG. 2).

While particular wavelength bands of s-polarized light are describedabove using red, green and blue colors as examples, those skilled in theart will appreciate that the description is exemplary only and is notintended to limit the scope of the disclosure.

Referring to FIG. 1, the s-polarized light emitted by the image source 1is incident on the transflective film 3 of the imaging window 2. Thetransflective film 3 has an average reflectivity greater than, forexample, 60% for wavebands within the FWHM of at least one of N spectrallines or bands of s-polarized light, whereby the image of the imagesource 1 is re-imaged through the imaging window 2. Further, the ambientlight outside the imaging window 2 can penetrate through the imagingwindow at a relatively high transmissivity (for example, 70% or more),which can form a clear and natural image when incident on the observer'seyes. Thus, the observer can simultaneously view the displayed images ofthe image source 1 as well as the ambient light.

FIG. 3 is an exemplary structural diagram of an imaging window accordingto an embodiment of the present disclosure. Referring to FIG. 3, theimaging window 2 includes a substrate having an inner surface and anouter surface. A transflective film 3 is disposed on the inner surfaceof the substrate, and an anti-reflection film 4 is further provided onthe outer surface.

In an embodiment, the image source 1 may use s-polarized light havingthree colors of red, green and blue. For example, the three colors arein the three wavebands of 630 nm±10 nm (red), 540 nm±10 nm (green), 450nm±10 nm (blue), respectively.

In at least one embodiment of the present disclosure, the transflectivefilm coated on the inner surface of the substrate has the followingoptical characteristics:

(1) for p-polarized light, the transflective film has a transmissivitygreater than 95% for all bands;

(2) for s-polarized light, the transflective film has an averagereflectivity greater than 70% for one or more optical wavebandscorresponding to the image source. For example, it has an averagereflectivity greater than 70% for the three bands of 630 nm±10 nm (red),540 nm±10 nm (green), and 450 nm±10 nm (blue), and has an averagetransmissivity greater than 70% for other wavebands.

The ghost image problem is first analyzed in the absence of ananti-reflection film. Assuming that the transflective film on the innersurface has an average reflectivity of 70% for a particular s-polarizedlight having one or more spectral lines or bands and has an averagetransmissivity greater than 70% for other bands; and the outer surfacehas a transmissivity of 90% for natural light. Then when the s-polarizedlight having the one or more optical bands is incident on thetransflective film and reflected by the transflective film, theintensity of the primary reflection light of the s-polarized light isabout 70% of the intensity of the incident light and the intensity ofthe s-polarized light refracted into the substrate is about 30% of theintensity of the incident light. The s-polarized light refracted intothe substrate will be reflected a second time by the outer surface film,and the light intensity after the secondary reflection is 30%*(1-90%);the secondary reflection light is incident on the transflective film,and the intensity of the light refracted by the transflective film is30%*(1-90%)*(1-70%)=0.9%.

It can be seen that the intensity of the refracted light is almostnegligible compared to the intensity of the primary reflection light.Therefore, no obvious ghost image will be formed in the presentdisclosure, thus overcoming the ghost image problem commonly encounteredin the prior art using s-polarized light.

The anti-reflection film coated on the outer surface of the substrateenables the outer surface of the imaging window to achieve an averagetransmissivity greater than 95% for the entire natural light spectrumunder normal daylight conditions.

The ghost image problem is analyzed in conjunction with thetransflective film and the anti-reflection film in the above-describedembodiment. Assuming that the transflective film on the inner surfacehas an average reflectivity of 70% for a particular s-polarized lighthaving one or more spectral lines or bands and has an averagetransmissivity greater than 70% for other bands; and the outer surfacehas a transmissivity of 95% for natural light due to the presence of theanti-reflection film. Then when the s-polarized light having the one ormore optical bands is incident on the transflective film and reflectedby the transflective film, the intensity of the primary reflection lightof the s-polarized light is about 70% of the intensity of the incidentlight and the intensity of the s-polarized light refracted into thesubstrate is about 30% of the intensity of the incident light. Thes-polarized light refracted into the substrate will be reflected asecond time by the anti-reflection film, and the light intensity afterthe secondary reflection is 30%*(1-95%); the secondary reflection lightis incident on the transflective film, and the intensity of the lightrefracted by the transflective film is 30%*(1-95%)*(1-70%)=0.45%.

It can be seen that with the specific structure in which the innersurface of the substrate is provided with a transflective film and theouter surface thereof is provided with an anti-reflection film, theimaging window of the present disclosure further significantly reducesthe ghost image problem.

The combined transmissivity and reflectivity in the embodiment isanalyzed in accordance with the optical characteristics of theabove-mentioned transflective film:

(1) reflectivity: because the image source adopts s-polarized light, andbecause the reflection characteristic of the coating has highcorrespondence with the image source, it can be known from thereflection characteristics of the coating that the average reflectivityR>70%;

(2) transmissivity: under general circumstances, assuming that theambient natural light contains 50% p-polarized light and 50% s-polarizedlight; for p-polarized light, the average transmissivity is above 90%;for s-polarized light, and the average transmissivity thereof in thevisible band (about 400 nm to 700 nm) is{(20+20+20)*0.3+[700−400−(20+20+20)]*0.7}/(700−400)≈62%; thus theaverage transmissivity for the entire natural lightT≈95%*50%+62%*50%=78.5%.

In summary, due to the use of an image source having characteristics anda coating having a reflection characteristic corresponding to the sourcecharacteristics of the image source, the embodiments of the presentdisclosure can achieve a sum of the average transmissivity for visiblelight T and the average reflectivity R for a particular light source ofthe image source greater than 148.5% (T+R>148.5%), thereby obtaining animaging effect with both high transmissivity and high reflectivity.

In addition, the narrower the FWHM of the light source spectrum and thereflection characteristic spectrum of the reflective film is, the highertransmissivity can be obtained while ensuring the reflectivity.

In an embodiment, the light source for a set of image sources shown inFIG. 2 includes a three-color laser with the peak positions of the threecolors being 445 nm (blue), 532 nm (green), 635 nm (red), respectively.The FWHM of each peak is only about 1-2 nm (see the laser projectionspectrum indicated by solid line in FIG. 2). With such a light source, aspecial corresponding transflective film is adopted for a particularangle range, for example, a range where the first angle is 55 degrees to65 degrees. The transflective film has a reflectivity of 95% fors-polarized light in the three spectral bands 444 nm to 446 nm, 531 nmto 533 nm, and 634 nm to 636 nm, has a transmissivity of 95% fors-polarized light outside the three bands, and has transmissivity of 95%for p-polarized light in the visible light range.

The combined transmissivity and reflectivity in the embodiment isanalyzed as follows:

(1) reflectivity: because the image source adopts s-polarized light, andbecause the reflection characteristic of the coating has highcorrespondence with the image source, it can be known from thereflection characteristic of the coating that the average reflectivityR>95%;

(2) transmissivity: assuming that the ambient natural light contains 50%p-polarized light and 50% s-polarized light; for p-polarized light, theaverage transmissivity is above 90%; for s-polarized light, and theaverage transmissivity thereof in the visible band (about 400 nm to 700nm) is {(2+2+2)*0.05+[700−400−(2+2+2)]*0.95}/(700−400)≈93.2%; thus, theaverage transmissivity for the entire natural lightT≈95%*50%+93.2%*50%=94.25%.

In summary, due to the use of an image source having polarization andspectra characteristics and a coating having a reflection characteristiccorresponding to the characteristics of the image source, theembodiments of the present disclosure can achieve a sum of the averagetransmissivity for visible light T and the average reflectivity R for aparticular light source of the image source greater than 189%(T+R>189%), thereby obtaining an imaging effect with both hightransmissivity and high reflectivity.

FIG. 4 is an exemplary flow chart of a displaying method according to anembodiment of the present disclosure. As shown, the method comprises:

step 401: providing an imaging window including a transparent substrateand a transflective film attached to the transparent substrate;

step 402: providing an image source capable of emitting s-polarizedlight;

step 403: causing the image source to emit s-polarized light to theimaging window in a first angle range with respect to the normal line,where the polarized light is directed toward the imaging window throughthe transflective film;

step 404: reflecting the s-polarized light by the transflective film.

The s-polarized light has N spectral lines or bands in the visible lightband, N is a positive integer not less than 1, and for example, N isequal to or greater than 3; the FWHM of the spectral lines or bands isless than or equal to 60 nm; within the first angle range, thetransflective film has an average reflectivity greater than 50% forwavebands within the FWHM of at least one of the N spectral lines orbands of the s-polarized light emitted by the image source; thetransflective film has an average reflectivity for visible light bandoutside the FWHM of the N spectral lines or bands of the s-polarizedlight emitted by the image source at least 5% and even 10% lower thanthe average reflectivity greater than 50% for wavebands within the FWHMof the N spectral lines or bands of the s-polarized light emitted by theimage source; where the transflective film has an average transmissivitygreater than 60% for p-polarized light in the visible range within thesecond angle range with respect to the normal line, where the firstangle range is 30 to 89 degrees, for example, 50 degrees to 75 degrees;and the second angle range is 30 degrees to 80 degrees, for example, 55degrees to 70 degrees.

In another embodiment, the s-polarized light has N spectral lines orbands in the visible light band, N is a positive integer not less than1, and for example, N is equal to or greater than 3; the FWHM of thespectral lines or bands is less than or equal to 60 nm; within the firstangle range, the transflective film has an average reflectivity in therange from 25% to 50% for wavebands within the FWHM of the 3 or morespectral lines or bands of the s-polarized light emitted by the imagesource, and has an average reflectivity for visible light band outsidethe FWHM of the N spectral lines or bands of the s-polarized light atleast 5% lower than the average reflectivity for the former; and thetransflective film has an average transmissivity greater than 60% forp-polarized light in the visible range within the second angle rangewith respect to the normal line.

The displaying system and method of the embodiments of the presentdisclosure can be applied in a variety of applications, e.g., to varioushead-up displays (HUDs) when used together with a base or pedestal; ofcourse, they can also be used in vehicles such as automobiles oraircrafts.

According to the embodiments of the present disclosure, light from theimage source and ambient light can be incident to the observer's eyes atthe same time to form a clear image, thereby presenting the image of theimage source to the observer's eyes without affecting the observer'sobservation of the external environment. In the embodiments of thepresent disclosure, s-polarized three-color lights are used as the imagesource of reflection, and meanwhile an imaging window with s-polarizednarrow-band high-reflectivity film is used. Because the spectral bandsof the image source and the transflective film are well matched, andbecause the s-polarized light is not affected by a Brewster's angle, thereflectivity of the light from the image source is greatly improved ascompared with the conventional technique, the utilization efficiency ofthe reflection light is high, and thus the entire optical system can berealized with a lower power consumption. In addition, because a highreflectivity can be obtained on a transflective film on the innersurface of the substrate, and because an anti-reflection film isprovided on the outer surface of the substrate, the ghost image problemcan be well suppressed. Further, the observer's perception of theambient light is almost not affected, because the same opticalinformation can be obtained from the p-polarized ambient light, even ifsome band of the s-polarized spectrum of the ambient light is filtered.

The foregoing description of the disclosed embodiments will enable thoseskilled in the art to carry out or use the present disclosure. It is tobe understood that the features disclosed in the above embodiments maybe used alone or in combination, unless otherwise specified. Numerousmodifications to these embodiments will be readily apparent to thoseskilled in the art, and the general principles defined herein may beimplemented in other embodiments without departing from the spirit orscope of the disclosure. Accordingly, the embodiments of the presentdisclosure disclosed herein is not limited to the specific embodimentsdisclosed, but is intended to cover modifications within the spirit andscope of the disclosure as defined by the appended claims.

What is claimed is:
 1. A heads-up displaying system, comprising: animaging window comprising a transparent substrate and a transflectivefilm attached to a first surface of the transparent substrate; an imagesource emitting light incident on the imaging window, and the lightemitted by the image source before reaching the transflective film onlycomprising s-polarized light, wherein the transflective film is formedby stacking at least two types of film layers having differentrefractive indexes, the transflective film comprises a first side and asecond side opposite to each other, the first side is attached to thefirst surface of the transparent substrate, the second side is incontact with the air, the second side is configured to directly reflecta first portion of the s-polarized light emitted from the image sourceto an observation region, and the image source and the observationregion are located on a same side of the transflective film, and thetransparent substrate comprises a second surface opposite to the firstsurface, the second surface reflects a second portion of the s-polarizedlight, and transmits a third portion of the s-polarized light to theair, the first portion of the s-polarized light, the second portion ofthe s-polarized light and the third portion of the s-polarized light areall s-polarized light; the s-polarized light emitted by the image sourcebefore reaching the transflective film has N spectral lines or bands ina visible light band, N is a positive integer not less than 1; the Nspectral lines or bands each have a FWHM (full-width at half-maximum);the N spectral lines or bands comprise at least three spectral lines orbands; and the average reflectivity of the transflective film for thethree spectral lines or bands of the s-polarized light is greater than60%, an average transmissivity of the transflective film for thes-polarized light outside the FWHM of the three spectral lines or bandsis greater than 60%.
 2. The heads-up displaying system according toclaim 1, wherein the N spectral lines or bands each have the FWHM(full-width at half-maximum) equal to or less than 60 nm, and for eachof the N spectral lines or bands in a visible spectra of the s-polarizedlight emitted from the image source, a major band is defined as aspectra band centered at a peak of the line or the band and expanding upto the FWHM; the transflective film reflects the s-polarized light at afirst angle with respect to a normal line, and transmits ambient lightat a second angle with respect to the normal line, the first angle is ina range from 30 to 89 degrees, and the second angle is in a range from30 degrees to 80 degrees; at the first angle, the transflective film hasan average reflectivity greater than 50% for at least one of the N majorbands of the s-polarized light, at the second angle, the transflectivefilm has an average transmissivity greater than 60% for p-polarizedlight in a visible range.
 3. The heads-up displaying system according toclaim 2, wherein a peak position of a first spectral line or band is ina range from 410 nm to 480 nm, a peak position of a second spectral lineor band is in a range from 500 nm to 565 nm, and a peak position of athird spectral line or band is in a range from 590 nm to 690 nm.
 4. Theheads-up displaying system according to claim 3, wherein the peakposition of the first spectral line or band is in a range from 440 nm to460 nm, the peak position of the second spectral line or band is in arange from 530 nm to 550 nm, and the peak position of the third spectralline or band is in a range from 620 nm to 640 nm, and the averagereflectivity of the transflective film for the three spectral lines orbands of the s-polarized light is greater than 70%, an averagetransmissivity of the transflective film for the s-polarized lightoutside the FWHM of the three spectral lines or bands is greater than70%, and the transflective film has the average transmissivity greaterthan 95% for the p-polarized light in the visible range.
 5. The heads-updisplaying system according to claim 3, wherein the peak position of thefirst spectral line or band is in a range from 444 nm to 446 nm, thepeak position of the second spectral line or band is in a range from 531nm to 533 nm, and the peak position of the third spectral line or bandis in a range from 634 nm to 636 nm, and the first angle is in a rangefrom 55 degrees to 65 degrees, the average reflectivity of thetransflective film for the three spectral lines or bands of thes-polarized light is greater than 95% at the first angle, an averagetransmissivity of the transflective film for the s-polarized lightoutside the FWHM of the three spectral lines or bands is greater than95%, and the transflective film has the average transmissivity greaterthan 95% for p-polarized light in the visible range.
 6. The heads-updisplaying system according to claim 1, wherein the composition of eachof the at least two types of film layers is at least one selected fromthe group consisting of tantalum pentoxide, titanium oxide, magnesiumoxide, zinc oxide, zirconium oxide, silicon dioxide, magnesium fluoride,silicon nitride, silicon oxynitride, and aluminum fluoride.
 7. Theheads-up displaying system according to claim 1, wherein ananti-reflection film is disposed on the second surface of thetransparent substrate, the anti-reflection film reflects the secondportion of the s-polarized light and transmits the third portion of thes-polarized light to the air; and the anti-reflection film increases anaverage transmissivity of the imaging window for visible light by atleast 3% or more as compared with a situation where the anti-reflectionfilm is not disposed.
 8. The heads-up displaying system according toclaim 7, wherein the N spectral lines or bands each have the FWHM(full-width at half-maximum) equal to or less than 60 nm, and for eachof the N spectral lines or bands in a visible spectra of the s-polarizedlight emitted from the image source, a major band is defined as aspectra band centered at a peak of the line or the band and expanding upto the FWHM; the transflective film reflects the s-polarized light at afirst angle with respect to a normal line, and transmits ambient lightat a second angle with respect to the normal line, the first angle is ina range from 30 to 89 degrees, and the second angle is in a range from30 degrees to 80 degrees; at the second angle, the transflective filmhas an average transmissivity greater than 60% for p-polarized light ina visible range.
 9. A vehicle comprising a displaying system accordingto claim
 1. 10. The vehicle according to claim 9, wherein the N spectrallines or bands each have the FWHM (full-width at half-maximum) equal toor less than 60 nm, and for each of the N spectral lines or bands in avisible spectra of the s-polarized light emitted from the image source,a major band is defined as a spectra band centered at a peak of the lineor the band and expanding up to the FWHM; the transflective filmreflects the s-polarized light at a first angle with respect to a normalline, and transmits ambient light at a second angle with respect to thenormal line, the first angle is in a range from 30 to 89 degrees, andthe second angle is in a range from 30 degrees to 80 degrees; at thefirst angle, the transflective film has an average reflectivity greaterthan 50% for at least one of the N major bands of the s-polarized light,at the second angle, the transflective film has an averagetransmissivity greater than 60% for p-polarized light in a visiblerange.
 11. The vehicle according to claim 10, wherein a peak position ofa first spectral line or band is in a range from 410 nm to 480 nm, apeak position of a second spectral line or band is in a range from 500nm to 565 nm, and a peak position of a third spectral line or band is ina range from 590 nm to 690 nm.
 12. The vehicle according to claim 9,wherein an anti-reflection film is disposed on the second surface of thetransparent substrate, the anti-reflection film reflects the secondportion of the s-polarized light and transmits the third portion of thes-polarized light to the air; and the anti-reflection film increases anaverage transmissivity of the imaging window for visible light by atleast 3% or more as compared with a situation where the anti-reflectionfilm is not disposed.
 13. The vehicle according to claim 12, wherein theN spectral lines or bands each have a FWHM (full-width at half-maximum)equal to or less than 60 nm, and for each of the N spectral lines orbands in a visible spectra of the s-polarized light emitted from theimage source, a major band is defined as a spectra band centered at apeak of the line or the band and expanding up to the FWHM; thetransflective film reflects the s-polarized light at a first angle withrespect to a normal line, and transmits ambient light at a second anglewith respect to the normal line, the first angle is in a range from 30to 89 degrees, and the second angle is in a range from 30 degrees to 80degrees; at the second angle, the transflective film has an averagetransmissivity greater than 60% for p-polarized light in a visiblerange.
 14. A heads-up displaying system, comprising: an imaging windowcomprising a transparent substrate and a transflective film attached toa first surface of the transparent substrate; an image source emittinglight incident on the imaging window, and the light emitted by the imagesource before reaching the transflective film only comprisings-polarized light, wherein the transflective film is formed by stackingat least two types of film layers having different refractive indexes,the transflective film comprises a first side and a second side oppositeto each other, the first side is attached to the first surface of thetransparent substrate, the second side is in contact with the air, thesecond side is configured to directly reflect a first portion of thes-polarized light emitted from the image source to an observationregion, and the image source and the observation region are located on asame side of the transflective film, and the transparent substratecomprises a second surface opposite to the first surface, the secondsurface reflects a second portion of the s-polarized light, andtransmits a third portion of the s-polarized light to the air, the firstportion of the s-polarized light, the second portion of the s-polarizedlight and the third portion of the s-polarized light are all s-polarizedlight; the s-polarized light emitted by the image source before reachingthe transflective film has N spectral lines or bands in a visible lightband, N is a positive integer not less than 1; the N spectral lines orbands each have a FWHM (full-width at half-maximum) equal to or lessthan 60 nm, and for each of the N spectral lines or bands in a visiblespectra of the s-polarized light emitted from the image source, a majorband is defined as a spectra band centered at a peak of the line or theband and expanding up to the FWHM; the transflective film reflects thes-polarized light at a first angle with respect to a normal line, andtransmits ambient light at a second angle with respect to the normalline, the first angle is in a range from 30 to 89 degrees, and thesecond angle is in a range from 30 degrees to 80 degrees; at the firstangle, the transflective film has an average reflectivity greater than50% for at least one of the N major bands of the s-polarized light, atthe second angle, the transflective film has an average transmissivitygreater than 60% for p-polarized light in a visible range; the Nspectral lines or bands comprise at least three spectral lines or bands,a peak position of a first spectral line or band is in a range from 410nm to 480 nm, a peak position of a second spectral line or band is in arange from 500 nm to 565 nm, and a peak position of a third spectralline or band is in a range from 590 nm to 690 nm; wherein the averagereflectivity of the transflective film for the three spectral lines orbands of the s-polarized light is greater than 60%, an averagetransmissivity of the transflective film for the s-polarized lightoutside the FWHM of the three spectral lines or bands is greater than60%; or, the peak position of the first spectral line or band is in arange from 440 nm to 460 nm, the peak position of the second spectralline or band is in a range from 530 nm to 550 nm, and the peak positionof the third spectral line or band is in a range from 620 nm to 640 nm,the average reflectivity of the transflective film for the threespectral lines or bands of the s-polarized light is greater than 70%, anaverage transmissivity of the transflective film for the s-polarizedlight outside the FWHM of the three spectral lines or bands is greaterthan 70%, and the transflective film has the average transmissivitygreater than 95% for the p-polarized light in the visible range.
 15. Aheads-up displaying system comprising: an imaging window comprising atransparent substrate and a transflective film attached to a firstsurface of the transparent substrate; an image source emitting lightincident on the imaging window, and the light emitted by the imagesource before reaching the transflective film only comprisings-polarized light, wherein the transflective film is formed by stackingat least two types of film layers having different refractive indexes,the transflective film comprises a first side and a second side oppositeto each other, the first side is attached to the first surface of thetransparent substrate, the second side is in contact with the air, thesecond side is configured to directly reflect the s-polarized lightemitted from the image source to an observation region, and the imagesource and the observation region are located on a same side of thetransflective film, the s-polarized light emitted by the image sourcebefore reaching the transflective film has N spectral lines or bands ina visible light band, N is a positive integer not less than 1; the Nspectral lines or bands each have a FWHM (full-width at half-maximum)equal to or less than 60 nm, and for each of the N spectral lines orbands in a visible spectra of the s-polarized light emitted from theimage source, a major band is defined as a spectra band centered at apeak of the line or the band and expanding up to the FWHM; thetransflective film reflects the s-polarized light at a first angle withrespect to a normal line, and transmits ambient light at a second anglewith respect to the normal line; the first angle is in a range from 50to 75 degrees, and the second angle is in a range from 55 degrees to 70degrees; at the first angle, the transflective film has an averagereflectivity greater than 50% for at least one of the N major bands ofthe s-polarized light; at the second angle, the transflective film hasan average transmissivity greater than 60% for p-polarized light in avisible range; the N spectral lines or bands comprise at least threespectral lines or bands, and the average reflectivity of thetransflective film for the three spectral lines or bands of thes-polarized light is greater than 60%, an average transmissivity of thetransflective film for the s-polarized light outside the FWHM of thethree spectral lines or bands is greater than 60%.
 16. The heads-updisplaying system according to claim 15, wherein, a peak position of afirst spectral line or band is in a range from 410 nm to 480 nm, a peakposition of a second spectral line or band is in a range from 500 nm to565 nm, and a peak position of a third spectral line or band is in arange from 590 nm to 690 nm %.
 17. The heads-up displaying systemaccording to claim 16, wherein the peak position of the first spectralline or band is in a range from 440 nm to 460 nm, the peak position ofthe second spectral line or band is in a range from 530 nm to 550 nm,and the peak position of the third spectral line or band is in a rangefrom 620 nm to 640 nm, and the average reflectivity of the transflectivefilm for the three spectral lines or bands of the s-polarized light isgreater than 70%, an average transmissivity of the transflective filmfor the s-polarized light outside the FWHM of the three spectral linesor bands is greater than 70%, and the transflective film has the averagetransmissivity greater than 95% for the p-polarized light in the visiblerange.
 18. The heads-up displaying system according to claim 16, whereinthe peak position of the first spectral line or band is in a range from444 nm to 446 nm, the peak position of the second spectral line or bandis in a range from 531 nm to 533 nm, and the peak position of the thirdspectral line or band is in a range from 634 nm to 636 nm, and the firstangle is in a range from 55 degrees to 65 degrees, the averagereflectivity of the transflective film for the three spectral lines orbands of the s-polarized light is greater than 95% at the first angle,an average transmissivity of the transflective film for the s-polarizedlight outside the FWHM of the three spectral lines or bands is greaterthan 95%, and the transflective film has the average transmissivitygreater than 95% for p-polarized light in the visible range.
 19. Theheads-up displaying system according to claim 15, wherein thecomposition of each of the at least two types of film layers is at leastone selected from the group consisting of tantalum pentoxide, titaniumoxide, magnesium oxide, zinc oxide, zirconium oxide, silicon dioxide,magnesium fluoride, silicon nitride, silicon oxynitride, and aluminumfluoride.
 20. The heads-up displaying system according to claim 15,wherein the transparent substrate comprises a second surface opposite tothe first surface, the second surface reflects a second portion of thes-polarized light, and transmits a third portion of the s-polarizedlight to the air, the first portion of the s-polarized light, the secondportion of the s-polarized light and the third portion of thes-polarized light are all s-polarized light.